The present invention is directed to semiconductor processes and devices.
Since the early days when Dr. Jack Kilby at Texus Instrument invented the integrated circuit, scientists and engineers have made numerous inventions and improvements on semiconductor devices and processes. The last five decades or so have seen a significant reduction in semiconductor sizes, which translate to ever increasing processing speed and decreasing power consumption. And so far, the development of semiconductor has generally followed Moore's Law, which roughly states that the number of transistors in a dense integrated circuit doubles approximately every two years. Now, semiconductor processes are pushing toward below 20 nm, where some companies are now working on 14 nm processes. Just to provide a reference, a silicon atom is about 0.2 nm, which means the distance between two discrete components manufactured by a 20 nm process is just about a hundred silicon atoms.
Manufacturing semiconductor devices has thus become more and more challenging and pushing toward the boundary of what physically possible. Huali Microeletronic Corporation™ is one of the leading semiconductor fabrication companies that has focused on the research and development of semiconductor devices and processes.
Conventional device structures based on silicon germanium (SiGe) technology were developed to produce field effect transistors (FET). For example, a SiGe technology has been developed for a p-channel metal oxide semiconductor (PMOS) transistor through depositing a buried, pseudomorphically strained SiGe layer capped by an unstrained silicon (Si) layer. The silicon cap layer is partially oxidized to form a gate dielectric. Due to an offset in the valence band, the holes can be confined to the SiGe channel. In this design, dislocations in the SiGe film can be avoided if the SiGe film thickness is made very thin. Fabrication of this device is compatible with state-of-the art complementary metal oxide semiconductor (CMOS) processing.
A further understanding of the nature and advantages of various embodiments may be realized by reference to the following figures. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.